Pat beef dry with paper towel and toss with flour until evenly coated.

Increase heat to medium high. Add beef a few pieces at a time, and brown on all sides. Add wine (if using) to pan and cook for 1 minute. Add broth to mixture and bring to boil. Reduce heat to low and simmer, partially covered, for 1 hour. Stir in pearl onions and continue to cook for 1 hour. Add mushroom caps and remove lid.

Simmer for 30 minutes or until beef is very tender. Just before serving, stir in sour cream and parsley. Reheat, but do not boil. Remove bay leaf before serving.

If adventurous, substitute different mushrooms like cremini or shiitake to enhance the flavour profile of this succulent dish.